The present invention generally relates to a heating or air conditioning system for a motor vehicle, with an exchangeable and selectively bypassable absorption filter which is arranged in a channel shaped housing and through which fresh air and/or circulating air can flow, and more particularly to an arrangement for preventing a processing result from being imparted despite the occurrance of untreated leakage air.
An arrangement of this type is disclosed by German, Published, Unexamined Patent Application 3,700,338. In the absorption mode of this arrangement it has become apparent that even very small quantities of untreated air, which enter the passenger space via leakage points by bypassing the absorption filter, impair the purification result to a greater or lesser extend according to a particular person's reaction.
Thus, an object of the present invention is to provide a heating/air conditioning system for preventing a processing result from being impaired in any way, despite the occurrence of untreated leakage air.
In a preferred exemplary embodiment of the invention, which is simple in terms of construction, leakage air is collected in a region of an absorption filter holder and a shut off bypass line by at least one continuous lip gasket which is secured on a bearing side of the absorption filter and on a pivoting flap of the bypass line. The lip gasket, with the respective associated bearing surface, forms a hollow chamber. This hollow chamber can easily be tapped, and the leakage air can be eliminated in a simple way.
To ensure that the hollow chamber continues to perform its function even at higher applied pressures, the lip gasket is stiffened on the fastening side by means of ribs transverse relative to its direction of extension according to one embodiment of the invention.
Simple conveyance of tapped air is obtained if the hollow chambers are connected to one another. A single tapping of one hollow chamber at an especially suitably sited location is then sufficient.
In the region of the absorption filter holder, the leakage air can also be collected in a cavity which is limited by two continuous gaskets bracing the absorption filter relative to a absorption filter holder on the inflow and flow off sides.
If a housing partition is located on that side of the dashboard facing away from the passenger space, according to a further embodiment of the invention, there is no need for a collection and controlled elimination of the leakage air possibly occurring along the housing partition when the absorption filter is subjected to pressure.
If a blower is placed in front of the channel-shaped housing, a cowl covering the housing partition and the blower can be secured to the dashboard, thereby forming a location which is closed off, with the exception of a closable air inflow port, and has a pressure level low when the blower is in operation and into which a bleed off line opens. There is therefore no need for a separate source at a low pressure level for removing the quantity of internal leakage air by suction.
However, it is also possible for the separated location, into which the bleed off line opens, to be formed by a vacuum source, such as, for example, the suction pipe, assigned to an internal combustion engine.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.